1. Field of the Invention
The present invention relates to a supporting sleeve for leg or arm stumps, namely a liner. More specifically, the present invention relates to a liner for surrounding a stump from its distal end with an elastic electrically insulating material, wherein the sleeve has at least partially a layer of a conductive material.
2. Description of the Related Art
The present invention involves a contact maker for the gate terminal of power semiconductor components in disc cells and power semiconductor modules.
The related art involves basic contact makers as a component of disc cells, as they are known, for example, from Heumann, “Grundlagen der Leistungselektronik” [“Fundamentals of Electronic Power”], Teubner Verlag, 6th edition, ISBN 3-519-06110-4, see page 37, and of preferably pressure-contacted power semiconductor modules, as they are known, for example, from DE 196 51 632 A1.
Pressure-contacted power semiconductor modules such as, for example, those according to DE 196 51 632 A1, are suitable for very high performance requirements regarding current-carrying capacity and reliability. This is why the gate terminal plays an equally important role here as the power terminals.
Pressure-type contacts of power terminals are sufficiently known as a tried and tested connecting technology from the production of semiconductor modules.
Unfortunately, for the contact of gate terminals, on the other hand, a great number of variations exist with different degrees of production complexity and different degrees of reliability not directly related to the former.
Soldered connections involving gate terminals and semiconductor components are known. Also known are different types of spring-biased pressure contacts, which have in common that they require a complex production that is unfortunately only manually possible and are substantially unreliable due to human error and other factors common in manufacturing.
Referring now to FIG. 1, a partial section through a disc cell 950 according to the conventional art is known. Disc cell 950 has an insulating member 954, preferably made of ceramic material. This insulating member 954 forms the housing of disc cell 950, and its top and bottom covers 956, 952 are implemented as shaped metal members. Disposed in the interior of disc cell 950 is a power semiconductor component 600.
In this conventional embodiment of disc cell 950, one of the shaped metal members 956 incorporates a recess 958. Disposed in recess 958 is the gate contact maker. It is implemented as an elastic wire element 962 with an insulating sleeve. The insulation covers only the portion of the wire element 962 that can come into contact with shaped metal member 956. The first end of the wire element 962 is arranged in a recess of insulating member 956 that is provided with a metal sleeve 964, and it is thus connected to it in an electrically conducting manner. The second end 960 of wire element 962 sits on the gate terminal of power semiconductor component 600. The arrangement in metal sleeve 964 and the shape of wire element 962 produce an elastic effect with an application of force on second end 960 of wire element 962 in the direction of power semiconductor component 600.
As shown, conventional disc cell 950 has the shortcoming that shaped metal member 956 must have a radially outwardly extending recess 958 to receive wire element 962. As a consequence, this design cannot be manufactured in a cost effective manner, and it is also not possible to automate the assembly of the contact maker.
Referring now to FIG. 2, a section through a conventional embodiment of a pressure-contacted power semiconductor module 900 is shown. Here, a metallic base plate 902, a plastic housing 908, and a plastic cover 910 are provided. Disposed on base plate 902, following an insulating layer, is a first shaped metal member 904, disposed on which is a power semiconductor component 600, and above same a second shaped metallic member 908. Second shaped metallic member 908 is placed under pressure by means of a pressure-contacting device 906 and thus pushes semiconductor component 600 against first shaped member 904 and the same against the base plate 902. In this manner a reliable electrical contact of semiconductor component 600 to the two shaped members 904, 908 is laboriously ensured, as well as a minimal thermal contact to base plate 902. The two shaped metallic members 904, 908 thus serve to contact the main terminals.
Gate terminal 610 of power semiconductor component 600 is contacted by means of a contact maker. This contact maker consists of a metallic wire element 914, which is fixed in a retaining means 912 of the housing. Provided, extending from this retaining means 912, is an electrically isolated wire connection 916 to an external connection. The second shaped metallic member 908 has a recess 920, in which wire element 914 is arranged and contacts gate terminal 610. Wire element 914, as well as its retaining element 912 are designed in such a way that wire element 914 establishes a spring force that is directed toward power semiconductor component 600. The gate terminal of power semiconductor module 900 is thus executed in pressure-contact technology as well.
This embodiment of the contact maker does have the shortcoming, however, that because of the recess 920 in second shaped member 908, the application of pressure on the power semiconductor component 600 does not take place in a radially symmetrical manner. An additional shortcoming is that the contact makers are implemented differently for different power classes of power semiconductor module 900 and corresponding different diameters of power semiconductor component 600. The complexity of the assembly of the contact maker also does not lend itself to a cost-effective production in this case.
An additional shortcoming of the contact maker for disc cells according to FIG. 1, and power semiconductor modules according to FIG. 2, is that the spring arm, i.e., the lateral expanse between the retaining means 964, 912 and the contact location, i.e., gate terminal 610 of power semiconductor component 600, is very large. This design of elastic wire elements 962, 914 impacts contact reliability, as the homogeneity of the spring force can be guaranteed across the production of a great number of disc cells or power semiconductor modules only with considerable effort.
Accordingly, there is a need for an improved contact maker for power semiconductor modules and disc cells that overcomes at least one of the detriments noted above.